In recent years, various research into disposing objects having various functions on the inner circumferential surface of a pneumatic tire has been conducted.
For example, an attachment method has been proposed in which tire tags (radio frequency identification tags), chips, or the like are attached to an inner liner or the like of a green tire using a surface fastener such as a hook and loop fastener, a hook and hook fastener, or the like (Japanese Unexamined Patent Application Publication No. 2005-517581A).
Additionally, a pneumatic tire has been proposed in which a surface fastener is vulcanization bonded to a region of the tire inner surface corresponding to the tread portion, and a noise absorbing member is attached to the tire inner surface via the surface fastener (Japanese Unexamined Patent Application Publication No. 2006-44503A).
The surface fasteners proposed in Japanese Unexamined Patent Application Publication Nos. 2005-517581A and 2006-44503A have preferable configurations in that a relatively strong engagement force is realized when attaching, and surface engagement can be achieved without causing problems of slight misalignments when attaching.
However, with surface fasteners, the state in which the individual engaging elements of the surface fastener are engaged with one another is not ideal due to the inner circumferential surface of the pneumatic tire being an annular, curved surface. With surface fasteners, portions of the edges and center portions become raised, and the amount of engagement force obtained varies (positional variation within the tire and variation from tire to tire). As a result, in some cases, the expected engagement force has not been obtained.
Additionally, after starting to use the tires for driving, partial physical deterioration occurs as a result of repetitive deformation and compaction of the entire tire over an extended period of time caused by rotation at high speeds in a state of relatively elevated temperatures, accompanied by deterioration and reduction over time of the engagement force over the entire surface fastener. This has led to difficulty in maintaining the desired engagement force over an extended period of time.
In addition, it is said that surface fasteners are desirable because they are capable of realizing surface engagement without problems such as slight positional misalignments. However, when the attached functional object is, for example, a measuring device, more reliable and accurate attachment of the object to a position has been demanded. Because of this lack of reliable and precise attachment, there are functional objects not suited to being attached with a surface fastener.
Also, the present inventors have previously proposed a pneumatic tire whereby the desired engagement force can be maintained over an extended period of time, with minimal physical deterioration or decline over time of the engagement force due to extreme usage conditions, including repetitive deformation and compaction over an extended period of time caused by tire rotation at high speeds in a state of relatively elevated temperatures. The obtained engagement force is large and is essentially free of variation in strength (positional variation within the tire and variation from tire to tire). Specifically, a pneumatic tire is proposed in which various types of objects with desired functions are attached by bonding mechanical fasteners, known as hooks or snaps, to a tire inner surface (see Japanese Unexamined Patent Application Publication Nos. 2012-25318A, 2012-25319A, 2012-240465A and the like).
Specifically, as a typical example, a pneumatic tire has been proposed having on the tire inner surface one of a pair of mechanical fasteners such as hook or snap or the like and that can be separated into two, as described in the Claims of Japanese Unexamined Patent Application Publication No. 2012-25318A (Claim 1). More specifically a pneumatic tire has been proposed in which the one fastener is configured including at least two components, and the two components are fixed sandwiching a tire member or a tire reinforcing member (Japanese Unexamined Patent Application Publication No. 2012-25318A, Claim 2).
According to the methods of attaching a desired object by bonding a mechanical fastener (hook or snap) to the tire inner surface described in Patent Documents 3 to 5, an object can be engaged and attached to the tire inner surface via the mechanical fastener. Normally the engagement force obtained is large, and there is no variation (positional variation within the tire and variation from tire to tire) in the magnitude of the engagement force. In addition, a superior pneumatic tire is achieved that enables installation in the prescribed position with good accuracy, the desired engagement force can be maintained over an extended period of time, with minimal deterioration or decline over time of the engagement force due to repetitive extreme usage conditions over an extended period of time.
In particular, by using as the first mechanical fastener attached to the tire inner surface a fastener that includes at least two components, the two components being fixed together by sandwiching a tire member or a tire reinforcing member, a superior mechanical fastener with increased fixing strength and good durability is achieved.
However, even with this format, when the object installed is a large object or a heavy object, depending on the road surface on which the tire is driven, the engagement between the mechanical fasteners can be released, and the object with a specific function falls off. In particular, when a comparatively large and heavy object with a specific function is installed by engaging the pair of mechanical fastener members together, the engagement between them can be easily released by high speed rotational movement of the tire, and after being released, the mechanical engagement force can be reduced by deformation or the like, so it may be considered that a sufficiently large engagement force cannot be obtained if they are engaged again.